Method and apparatus for continuous zig-zag web folding



United States Patent Inventors Kenneth G. Cooke;

Curt G. Adomeit, Rochester; Leo David Delaney, Webster, New York Appl. No. 786,284 Filed Dec. 23, 1968 Patented Dec. 1, 1970 Assignee Eastman Kodak Company Rochester, New York a corporation of New Jersey METHOD AND APPARATUS FOR CONTINUOUS ZlG-ZAG WEB FOLDING 19 Claims, 3 Drawing Figs.

US. Cl 270/69, 270/6l, 270/79 Int. Cl B65h 45/00 F icld of Search 270/61, 69,

I [5 6] References Cited UNITED STATES PATENTS 1,290,800 1/1919 Teall 270/79 Primary Examiner-Jerome Schnall Assistant Examiner Paul V. Williams Att0rneysWalter O. Hodsdon, P. R. Holmes and R. L.

Randall ABSTRACT: A continuous zigzag web folding apparatus having an endless drive member with a plurality of blades extending outwardly therefrom which contact only one surface of the web. Air jet means are directed at the web to maintain it in contact with the blades as they are advanced to assure that the web is folded.

Patented Dec. 1, 1970 3,544,099

heet 1 of 2 KENNETH COO/(E CUR? ADOME/T L. 04m? DELAA/[y Patented Dec. 1, 1970 3,544,099

IIBIIEILT DII mncmmm L. DAV/D DELA/VEV INVENTORS A T TORNE Y5 METHOD AND APPARATUS FOR CONTINUOUS ZIG- ZAG WEB FOLDING BACKGROUND OF THE INVENTION Many process and communications systems, including data production, accumulation or transmittal, telemetry and the like, require high speed recording of the information involved. Many times the information produced is of such short duration that a relatively permanent record must be made for the information to be useable. Examples of high speed recording include computer output recording apparatus and oscilloscope trace recording apparatus.

More specifically, high speed information recording apparatus is utilized in recording telemetry information from nonrepeatable and/or nonaccessible sources of information such as space vehicles or other remotely operated equipment. The record of such information is generally made on webs of a material having a coated or sensitized surface arranged to register the information desired. The sensitized surface may record the information photographically, thermally, with ink or by any other method known in the art.

Many such recording systems must operate intermittently and yet be capable of extremely high speed. It has thus been found that zigzag or accordion-folded webs are more satisfactorily utilized for recording the information than are webs in roll form. One of the advantages of using a zigzag folded web is the elimination of the inertia of a supply roll of the web material which tends to reduce the speed at which movement of web past the recording station may be started and stopped. Another advantage is the ease of access to the information recorded on the surface of the folded web, since a long strand of the web need not be unrolled to reach a portion of the web at the middle or center of the strand as would be the case were the web in roll form.

Apparatus for folding a continuous web in zigzag or accordion form have long been in use, often comprising two sets of interleaving blades arranged to fold the web in zigzag shape after it has been cross-perforated at the desired fold lines. However, folding apparatus of the prior art engages both surfaces of the web to achieve the desired folding. This method of folding has been acceptable with many types of webs. However, it has been found that it is extremely undesirable to contact the sensitized or coated surface of the information recording webs noted above because of the possibility of abrading or otherwise damaging the sensitized surface. Likewise, it is undesirable to permit relative motion between the sensitized surfaces after the web has been folded. With a damaged surface, the web might either not properly accept or record the data or may give the appearance of false information. This is particularly true when oscillograph traces are recorded, which traces may appear merely as a plurality of very fine, closely spaced lines that can easily be confused by the presence of surface scratches on the web.

In addition, it has been found necessary to accurately fold such information recording webs so that they may be compactly stacked. Should the folder mechanism not accurately fold the web along the fold perforations, the varying lengths of the adjacent sheets causes the stack of the folded web to lean or otherwise depart from the shape of the container in which it is to be placed. As a result, less than full capacity may be held by the container or the web may become jammed as it is transported past the recording station, either of which is highly undesirable.

It is thus apparent that a method and apparatus for accurately folding a web, perforated transverse to its longitudinal dimension, in a zigzag configuration at high rates of production while contacting only the unsensitized surface is necessa ry to permit the information recording operations noted above.

SUMMARY OF THE INVENTION Accordingly, the present invention provides apparatus for zigzag folding a web comprising a plurality of blades movable lit along a closed path having a pair of curved portions connected by a substantially straight portion. Each of the blades extends substantially perpendicularly outwardly from the path whereby the blades are held in substantially parallel close proximity as they move along the straight portion of the path and are angularly separated as they round the curved portions of the path. The blades operate as a plurality of cooperating pairs, each pair arranged to contact a surface of the web in spaced relationship as they round a first curved portion of the path. Air jet means is provided at both sides of the outer end of the leading blade rounding the first curved portion of the path to form an outside fold in the web. A second air jet means is directed at the web between the blades as they are advanced into parallel relationship to force said web toward the inner ends of the blades whereby the web is gripped between the inner ends of said pair of blades to form an inside fold. The web is then advanced with the blades and is released from between the inner ends of the pair of blades as the outer ends of the blades are moved angularly apart at a second curved portion of the path. Means is provided to remove the folded web from the blades as it is released.

Moreover, the present invention provides web folding apparatus wherein the length of the blades and the radius of the first curved portion of the closed path is such that as the blades round the first curved portion of the path the distance between adjacent blade tips is substantially equal to the distance between alternate, outside folds in the web.

Also, the present invention provides a folding apparatus wherein each blade has a deformable pressure pad disposed on both sides of the inner end thereof which mate with pressure pads on adjacent blades as the blades are moved into parallel relationship to grip the web therebetween to assure the formation of an inside fold.

More specifically, the present invention provides apparatus for folding a web having a plurality of equispaced transversely extending perforated lines and a first coated surface and a second surface. The apparatus comprises a plurality of blades connected to and movable with a pair of laterally spaced, vertically arranged endless chain members. Each of the blades is connected at opposite sides of one end thereof to each of said chains and extends substantially perpendicularly outwardly from the path of the chains. The blades function as a plurality of cooperating pairs. A pair of vertically spaced chain drive and support members from a vertical oval chain path having substantially vertical straight sides whereby the blades are held in substantially parallel close proximity as they move vertically in the path and are angularly separated as they round the ends of the path. The outer ends of adjacent pairs of blades are arranged to contact the second surface of the web and to mate with alternate perforated lines in the web as the blades round the upper end of the chain path. A flexible web supporting sheet is connected to adjacent blades near the outer ends thereof and have a central fold line arranged to mate with the inner ends of the adjacent blades when they are in substantially parallel proximity, the central fold line of the web supporting sheet being arranged to-mate with the perforated line in the web between the alternate perforated lines. Means is provided for directing a pair of air jets at both sides of the outer end of the leading blade of the pair of adjacent blades rounding the upper end of the chain path to form an outside fold in the web at the perforated line over the outer end of the leading blade. A means is provided for directing a jet of air at the perforated line in the web between the adjacent blades as they are moved into parallel relationship to force the web toward the inner ends of the blades and the fold line in the web supporting sheetwhereby the web is gripped between the folded web supporting sheet and the inner ends of said adjacent blades. The web is linearly advanced downwardly with the blades and is released from between the inner ends of blades as the outer ends of the blades are moved angularly apart as the blades round the lower end of the chain path. A pair of rotating wheel members is disposed adjacent the lower side of the pair of chains, adjacent the position the web is released from between the inner ends of the blades. The rotating wheel members rotate within slots formed in the blades from the outer ends to the inner ends thereof. The rotating wheel members are arranged to extend into the blade slots as the blades round the lower end of the chain path. The wheel members rotate in a direction such that the portion of the wheel members in the blade slots are moving in a direction opposite the movement of the blades at that point. The outer periphery of the rotating wheel members thus engage the second surface of the web as the web is released from between the inner ends of the blades so that the folded web is removed from the folder apparatus.

In addition, the present invention provides a method of zigzag folding, transverse to its longitudinal dimension, a web having a first coated surface and a second surface. The method comprises the steps of feeding the web to the folder apparatus and contacting the second surface of the web with the outer ends of a pair of angularly spaced moving blades. An outside fold is formed in the web over the outer end of the leading blade by directing air at both sides of the outer end of the leading blade. The outer ends of the pair of blades are brought together while angularly advancing the blades and the web. Air is directed at the web between the adjacent blades to force the web toward the inner ends of the blades. An inside fold is formed in the web between the adjacent blades to force the web toward the inner ends of the blades. An inside fold is formed in the web between adjacent blades by angularly advancing the blades and the web to move the blades into parallel relationship. The blades and said web are then linearly advanced and the web is released from between the inner ends of said blades by moving the .outer ends of the blades angularly apart.

The various features of novelty which characterize the present invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, its operating advantages and the specific objects obtained by its use, reference should be had to the accompanying drawings and descriptive matter in which the preferred embodiments of the present invention are illustrated and described.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation view of a folder apparatus embodying the present invention;

FIG. 2 is a detail view of the blade connection to the folder drive member; and

FIG. 3 is a schematic illustration of the cooperation between the folder blades and the air nozzles.

DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present zigzag web folding apparatus is shown in FIG. 1 and generally comprises three subcomponents: a folder apparatus 10, a folded web pickoff l2, and a stack conveyor 14.

The web folding apparatus consists of a pair of spaced, generally upright support columns 16 arranged to support and aline three pairs of vertically spaced shaft journals (not shown). Three vertically spaced shafts, 18, 19 and are rotatably supported in the respective journals and extend horizontally between the support columns 16. The upper shaft 18 is provided with a pair of chain drive and support members or sprockets 24, one at each end thereof, adjacent the support columns 16 and the lower shaft 20 is provided with a corresponding pair of sprockets 26. The middle shaft 19 is provided with a pair of idler sprockets 27 which operate to control the chain path between the upper and lower shafts. A pair of parallel endless drive members or chains, and 32, extend between the corresponding sprockets on the spaced upper and lower shafts and follow a pair of parallel vertical oval chain paths having a pair of curved portions connected by substantially vertical straight sides.

A plurality of planar blades 36 having a size generally equal to the size of each sheet of the folded web are connected via a L-shaped support bar 33 to and are moveable with the chains 30 and 32. The blades and support bars extend between both chains 30 and 32 and are connected at opposite sides of the inner end thereof to both chains. The blades extend substantially perpendicularly outwardly from the path of the chains. As shown in the drawing, the blades, as they move about the oval path of the chains, are held in substantially parallel close proximity as they move vertically in the path and are angularly separated as they round the ends of the path.

A pair of vertical guide bars 34 are disposed adjacent the outer surface of each of the spaced sets of sprockets 24, 26 and 27 and form a straight surface tangential to the upper and lower sprockets along the vertical side of the chain path where the chains are moving downwardly. As shown in FIG. 2, the inner end of the blades 36 are provided with a cutout 35 on either side thereof which permit the guide bars 34, which are spring-loaded and supported from the support columns 16, to engage the outer face of the support bar 33 to hold it in contact with the idler sprockets 27. The guide bars 34 function to support and guide the L-shaped support bars 33 between the upper and lower sprockets to assure that the blades 36 are maintained in parallel relationship with no relative motion therebetween which could damage the surface of the web being folded. The blades 36 are also provided with a pair of slots 39 extending inwardly from the outer ends thereof. The purpose of these slots will become apparent hereinafter.

A flexible web supporting sheet 38, having a preformed central fold line disposed midway between the ends thereof, is connected between the outer ends of adjacent blades 36 and is provided with slots therein corresponding to slots 39 in the blades. The flexible web supporting sheet is formed of a relatively stiff, yet flexible, material which folds at the preformed central fold line thereof. It has been found that a preferred fold is obtained utilizing two sheets joined together at the fold line by a thin plastic material having good folding characteristics. The web supporting sheet 38 functions to support the web between the blades 36 to prevent it from folding from its own weight. It also provides a predetermined fold line along which the inside fold of the web is formed. Likewise, the supporting sheet acts 'to prevent relative motion between the coated surface of the web as the inside fold is formed.

A deformable pressure pad 40 is connected to each side of, and extends across the width of the inner end of the blade 36, adjacent the joint of the blade with L-shaped support bar 33. The pressure pad mates with pressure pads on adjacent blades when they are in parallel relationship to grip the web supporting sheet and the web therebetween to assure the formation of an inside fold.

The folding apparatus 10 accepts a web 42, which is preperforated with a plurality of equispaced, transversely extending perforated lines before it enters the folding apparatus. The web may be supplied either directly from a perforating apparatus or from a supply spool, having been previously perforated and stored. While it is advantageous to supply the web to the folder apparatus in a substantially horizontal plane, as shown, minimizing the headroom necessary, it will be understood that the web can approach the folder apparatus in other than a horizontal plane.

The operation of the folder is such that the blades 36 act as cooperating pairs, joined by the flexible web supporting sheet 38. Thus, each blade is both a leading blade and a trailing blade of two adjacent cooperating pairs. The relationship between the length of the blades 36 and the radius of the upper sprockets 24 is so proportioned that, for a given spacing of the perforated lines along the length of the web, as the blades round the upper end of the chain path about sprockets 24 and are angularly displaced the maximum distance possible, the distance between adjacent blade tips is substantially equal to the distance between alternate perforated lines in the web. Likewise, the length of each blade from the inner end thereof, adjacent chains 30 and 32, to the outer end is just greater than the spacing between adjacent perforated lines in said web. The distance between the outer end of the blade and the centerfold line of the web supporting sheet 38 is also substantially equal to the distance between adjacent perforated lines in said web.

A pair of gas or air nozzles 44 are directed at the opposite sides of the outer end of the leading blade of a pair of cooperating blades at the point of maximum angular displacement between the blades at the upper end of the oval chain path. A separate air nozzle 46 is directed at the perforated line in the web between the cooperating pair of blades as they are advanced into parallel relationship after rounding the upper end of the chain path.

In operation, the perforated web is threaded into the folding apparatus with a first perforated line in alinement with the outer end of a leading blade of a cooperating pair of blades rounding the upper end of the chain path. The pair of chains are driven by a power source (not shown) connected through one or both of the shafts 18 and 20 to the sprockets connected thereto to advance the leading blade beyond the upper end of the chain path. As the leading blade advances and moves downwardly along the vertical portion of the path, the trailing blade (which is, at the same time, the leading blade of the next succeeding pair of cooperating blades) mates with the next alternate perforated line in the web. The trailing blade then moves downwardly to the vertical portion of the path and the web is gripped between adjacent pressure pads 40 of the leading blade and the trailing blade and the web supporting sheets 38, setting the inside fold.

Inasmuch as it is desirable to contact only the uncoated surface of the web and to avoid marking the coated surface, the web is fed to the folder apparatus by a feed roll system which accurately meters the web to the folder without damaging the coated surface. Between the feed roll and the folder, the web is generally not tensioned. Accordingly, the air nozzle 46 is arranged to constantly direct a jet of gas or air at the web to maintain it in alinement with the folder apparatus. As .the outer end of each leading blade A, see FIG. 3, reaches the location A rounding the upper end of the chain path where it is separated the maximum distance from the cooperating trailing blade, the air nozzles 44 are actuated to provide a short jet of high velocity air which force the web over the outer end of the respective blade to form the outer fold at the perforated line. As the blades B are further advanced into parallel relationship B, the air nozzle 46 directs the jet of air at the perforated line in the web between adjacent blades to force the web toward the inner ends of the blades and the fold line in the web sup- I porting sheet to form an inner fold in the web. As the tip of the blade passes nozzle 46, the flow of air therethrough is reduced to minimize disturbing the outer fold of the web and yet still provide enough air to maintain the web in alinement with the blades. The nozzles are supplied with air through activators (not shown) that are preferably operated by the folder drive to supply air to the respective nozzles when the blades are in the proper orientation.

The web is advanced with the downwardly moving blades (and subsequent folds are formed by succeeding blades) to the point where the blades start to round the lower portion of the chain path, at which time the cooperating pair of blades again angularly separate, releasing the web from between the inner ends of the blades. After releasing the web at the-lower end of the chain path the blades travel upwardly on the opposite straight portion of the chain path to repeat the cycle by picking up the web at a new perforated line.

Thus it will be seen that the web is positively and uniformly folded by the present folder apparatus without physically contacting the sensitized or coated surface thereof. Moreover, with the utilization of the air jets, the web supporting sheets, and the pressure pads, no relative motion occurs between the adjoining sensitized surfaces of the web folds minimizing any potential damage thereto.

The folded web pickoff assembly 12 comprises a pair of rotating wheel members 48 carried by a horizontal shaft 50 supported by columns 16. The shaft 50 is substantially vertically alined with shafts l8, l9 and 20 and is spaced below shaft 20 a distance such that the outer periphery of the wheel members do not contact the web support sheet 38 when adjacent blades 36 are at their greatest separation as they round the lower end of the chain path. The outer periphery of the wheel members are provided with a high friction surface such as rubber. As the blades round the lowermost portion of the chain path, slots 39 in the blades provide clearance for the rotating wheel members. The wheel members are driven so that the upper portion of the periphery thereof is moving in a direction opposite to the movement of the blades at that point.

Thus, should the folded web be held in contact with the blades, even after the inner fold is released, such as by any vacuum produced by the blades at high speeds, the rotating wheel members will contact the second surface of the web and force it away from the blade surface as the blade passes over the wheel members.

As the folded web is released from the blades, it is deposited on the stack conveyor 14 in a horizontal accordion arrangement. The stack conveyor comprises a pair of interleaved horizontal conveyor belts 52 and 54 disposed at the lower side of the folder. The belts 52 and 54 consist of a plurality of parallel bands whereby belt 52 permits the rotating wheel members 48 to extend through the upper surface thereof. The band formation of belt 54 permits it to overlap belt 52. Thus, belt 52 is driven at a surface speed such that the folded web deposited thereon is removed from the folder as rapidly as the web is released from the blades. Belt 54, however, is driven at a speed less than that of belt 52 whereby the folded web is compacted. The web may then be cut into desired lengths and packed.

Thus, the present invention provides a method and apparatus for zigzag folding, transverse to its longitudinal dimension, a web 42 having a plurality of equispaced, transversely extending, perforated lines. The web may have a first coated surface susceptible to physical marking, and a second surface not susceptible to contact marking. The web is fed to the folder apparatus, preferably in a horizontal orientation, with the first coated surface up. The second surface of the web 42 mates with the outer ends of a pair of angularly spaced moving blades 36 having a flexible web supporting sheet 38 connected to and extending therebetween. The outer ends of the blades are arranged to mate with alternate perforated lines in the web, and the web supporting sheet has a fold line arranged to mate with the perforated line in the web between the alternate perforated lines. The web is held in alinement with the blades by an air jet from nozzle 46. The outside fold is formed in the web at the perforated line over the outer end of the leading blade with high velocity jets of air from nozzles 44, which are at opposite sides of the outer end of the leading blade, as the leading blade reaches the point of maximum separation from the trailing blade. The outer ends of the pair of blades are brought together while angularly advancing the blades and the web and'a jet of air is directed at the perforated line in the web between the adjacent blades to force the web toward the inner ends of the blades and the fold line in the web supporting sheet. The inside fold is formed in the web at the perforated line between adjacent blades by angularly advancing the blades and the web to move the blades into parallel relationship, and gripping the web between the folded web supporting sheet and the inner ends of the adjacent blades. The blades and the web are linearly advanced downwardly and the web is released from between the inner ends of the blades by moving the outer ends of the blades angularly apart. The second surface of the web is contacted by the upper surface of the rotating wheel members and removal from the folder blades is assured.

The folder apparatus, the folded web pickoff assembly, the folded web conveyor, and the air jet actuators are preferably driven by a common power source through a gear drive or other nonslip power transmission device so that the operation of these elements is synchronized. Thus, the air nozzles 44 are actuated precisely at the tifn e th e blades are in the proper orientation. Likewise, the rotating wheel members and the folded web conveyor are driven at a speed relative to the speed of the folder that assures that the web is not damaged.

While, as noted above, some relative sizes are important in the arrangement of the present invention, it will be appreciated that the width of the apparatus referred to is for example only. it will be apparent that narrower webs can be satisfactorily folded on apparatus primarily intended for wider webs, although the distance between folds cannot be so readi ly varied.

The present invention thus provides a zigzag web folder apparatus which accurately and consistently folds a web at high rates of production. The present apparatus accomplishes the foregoing while contacting only one surface of the web, permitting its utilization for folding webs having a surface susceptible to damage from contact with or movement over contacting surfaces.

The invention has been described in detail with particular reference to preferred embodiments thereof, but it will be un derstood that variations and modifications can be effected within the spirit and scope ofthe invention.

We claim:

1. Apparatus for zigzag folding a web comprising a plurality of blades movable along a path having a pair of curved portions connected by a substantially straight portion, each of said blades extending outwardly from the path whereby said blades are held in substantially parallel proximity as they move along the straight portion of the path and are angularly separated as they round the curved portions of the path, said blades operating as a plurality of cooperating pairs, a pair of blades arranged to contact a surface of the web in spaced relationship as the blades round a first curved portion of the path, jet means directed at the web at both sides of the outer end of a leading blade of the pair of blades rounding said first curved portion of the path to form an outside fold in the web, and jet means directed at the web between the blades as they are advanced into parallel relationship to force said web toward the inner ends of the blades whereby the web is gripped between the inner ends of said pair of blades to form an inside fold and is advanced with said blades, said web being released from between the inner ends of said pair of blades as the outer ends of the blades are moved angularly apart as the blades round a second curved portion of the path.

2. The invention according to claim l wherein means to remove the folded web from the blades is disposed adjacent the second curved portion ofthe blade path.

3. The invention according to claim ll wherein the length of the blades and the radius of the first curved portion of the closed path is such that as the blades round the first curved portion of the path the distance between adjacent blade tips is substantially equal to the distance between adjacent outside folds in said web.

4. The invention according to claim 1 wherein the blades are connected to and extend outwardly from a drive chain which follows an oval path.

5. Apparatus for zigzag folding a web transverse to its longitudinal dimension, said web having a plurality of equispaced transversely extending perforated lines and a first coated surface and a second surface, said apparatus comprising a plurality of blades connected to and movable with a substantially endless drive member following a substantially oval path, said blades operating as a'plurality of cooperating pairs, each of said blades extending perpendicularly outward from the path of the drive member whereby said blades are held in substantially parallel close proximity as they move along the straight portion of the path and are angularly separated as they round the ends of the path, the outer ends of adjacent pairs of blades arranged to contact the second surface of the web and to mate with alternate perforated lines in said web as the blades round a first end of the path, mca for directing a pair of high velocity air jets at opposite sides of the outer end of the leading blade of the pair of adjacent blades rounding a first end of the path to form an outside fold in the web at the perforated line over the outer end of the leading blade, means for directing a jet of air at the perforated line in said web between the adjacent blades as they are moved into parallel relationship to force said web toward the inner ends of the blades whereby the web is gripped between the inner ends of said adjacent blades and is linearly advanced with said blades, said web being released from between the inner ends of said blades as the outer ends of the blades are moved angularly apart as the blades round a second end of the path, and means disposed adjacent the second end of said path where the web is released from between the inner ends of said blades arranged to engage the second surface of the ,web to remove the web from the blades.

The invention according to claim 5 wherein each blade has a deformable pressure pad disposed on both sides of the inner end thereof which mate with pressure pads on adjacent blades as the blades are moved into parallel relationship to grip the web supporting sheet and the web therebetween to assure the formation of an inside fold.

7. The invention according to claim 5 wherein said drive member comprises a pair ofendless chain members and a pair of spaced chain drive and support members forming an oval chain path, and the length of the blades and the radius of the chain drive and support member at the first end of the path is such that the distance between adjacent blade tips as they round the first end of the path is substantially equal to the distance between alternate perforated lines in said Web.

S. The invention according to claim '7 wherein a chain support member extends between said drive members to restrain said chains from departing from the straight portion of said path.

The invention according to claim '7 wherein said chain path is substantially vertical with the web being contacted by the blades at the upper end of the path and the web being released at the lower end of the path.

it). The invention according to claim 5 wherein the means to remove the web from the blades includes a pair of rotating wheel members disposed adjacent the second end of said endless drive member path, the outer surface of the wheel members arranged to engage the second surface of the web and to force the web away from the blades rounding the second end of the path.

it. The invention according to claim 10 wherein said blades are provided with a pair of slots extending inwardly from the outer end thereof which permits the outer end of said blades to move uast the outer periphery of said rotating wheel members.

Apparatus for zigzag folding a web transverse to its longitudinal dimension, said web having a plurality of equispaced transversely extending perforated lines and a first coated surface and a second surface, said apparatus comprising a plurality of blades connected to and movable with a pair of laterally spaced vertically arranged endless chain members, each of said blades connected at opposite sides of one end to each of said chains and extending perpendicularly outwardly from the path of the chains, said blades operating as a plurality of cooperating pairs, a pair of vertically spaced chain drive and support members forming a vertical oval chain path having substantially vertical straight sides whereby said blades are held in substantially parallel close proximity as they move vertically in the path and are angularly separated as they round the ends of the path, means for feeding said web horizontally to the upper end of said chain path, the outer ends of adjacent pairs of blades arranged to contact the second surface of the web and to mate with alternate perforated lines in said web as the blades round the upper end of the chain path, a flexible web supporting sheet connected to adjacent blades near the outer ends thereof and having a central fold line arranged to mate with the inner ends of the adjacent blades when they are in substan "ly parallel proximity, the central fold line of the web supporting she t arranged to mate with the perforated line in said web between said alternate perforated lines, means for directing a pair of air jets'aTopposite sides of the outer end of the leading blade of the pair of adjacent blades rounding the upper end of the chain path to form an outside fold in the web at the perforated line over the outer end of the leading blade, means for directing a jet of air at the perforated line in said web between the adjacent blades as they are moved into parallel relationship to force said web toward the inner ends of the blades and the fold line in said web supporting sheet whereby the web is gripped between the folded web supporting sheet and the inner ends of said adjacent blades and is linearly advanced with said blades downwardly, said web being released from between the inner ends of said blades as the outer ends of the blades are moved angularly apart as the blades round the lower end of the chain path, each of said blades having a pair of slots extending from the outer end of said blades toward the inner end thereof, each of said web supporting sheets having a pair of slots extending from the outer end thereof toward the central fold line and corresponding to the slots in said blades, a pair of rotating wheel members disposed adjacent the lower end of the chain path arranged to extend into said blade slots as the blades round the lower end of the chain path, the upper portion of said wheel members arranged to move in a direction opposite the movement of the blades at that point whereby the outer periphery of said wheel members engage the second surface of the web as the web is released from between the inner ends of the blades to remove the web from the folder.

13. The invention according to claim 12 wherein the length of the blades and the radius of the upper chain drive members is such that as the blades round the upper end of the chain path the distance between adjacent blade tips is substantially equal to the distance between alternate perforated lines in said web.

14. The invention according to claim 12 wherein each blade has a deformable pressure pad disposed on both sides of the inner end thereof which mate with pressure pads on adjacent blades as the blades are moved into parallel proximity to grip the web supporting sheet and the web therebetween to assure the formation of an inside fold.

15. The method of zigzag folding a web transverse to its longitudinal dimension, said web having a first coated surface and a second surface, comprising the steps of feeding the web to the folder apparatus, contacting the second surface of the web with the outer ends of a pair of angularly spaced moving blades, forming an outside fold in the web over the outer end of the leading blade by directing air at both sides of the outer end of the leading blade, bringing the outer ends of the pair of blades together while angularly advancing the blades and the web, directing air at said web between the adjacent blades to force said web toward the inner ends of the blades, forming an inside fold in the web between adjacent blades by angularly advancing the blades and the web to move the blades into parallel relationship, linearly advancing said blades and said web, and releasing the web' from between the inner ends of said blades by moving the outer ends of the blades angularly apart.

16. The invention according to claim 15 wherein the web is removed from the blades by engaging the second surface of the web with a rotating wheel member moving in a direction opposite to that of the blades.

17. The invention according tociaim 15 wherein said web is introduced horizontally to the folding apparatus and the blades contact the lower surface of the web and move the web downwardly to the location where the web is released.

18. The method of zigzag folding a web transverse to its longitudinal dimension, said web having a plurality of equispaced transversely extending perforated lines and a first coated surface and a second surface, comprising the steps of feeding the web to the folder apparatus, contacting the second surface of the web with the outer ends of a pair of angularly spaced moving blades, the outer ends of the blades arranged to mate with alternate perforated lines in said web, forming an outside fold in the web at the perforated lineover the outer end of the leading blade by directing a pair of air jets at opposite sides of the outer end of the leading'blade, bringing the outer ends of the pair of blades together while angularly advancing the blades and the web, directing a jet of air at the perforated line in said web between the adjacent blades to force said web toward the inner ends of the blades, forming an inside fold in the web at the perforated line between adjacent blades by angularly advancing the blades and the web to move the blades into parallel relationship and gripping the web between the inner ends of said adjacent blades, linearly advancing said blades and said web downwardly, releasing the web from between the inner ends of said blades by moving the outer ends of the blades angularly apart, and engaging the second surface of the web with a rotating wheel member moving in a direction opposite to that of the blades.

19. The method of zigzag folding a web transverse to its longitudinal dimension, said web having a plurality of equispaced transversely extending perforated lines and a first coated surface and a second surface, comprising the steps of horizontally feeding the web to the folder apparatus with the first coated surface up, contacting the second surface of the web with the outer ends of a pair of angularly spaced moving blades having a flexible web supporting sheet connected to and extending therebetween, said blades being connected to and driven by a pair of laterally spaced vertical endless chains, the outer ends of the blades arranged to mate with alternate perforated lines in said web, said web supporting sheet having a fold line arranged to mate with the perforated line in said web between said alternate perforated lines, forming an outside fold in the web at the perforated line over the outer end of the leading blade by directing a pair of air jets at opposite sides of the outer end of the leading blade, bringing the outer ends of the pair of blades together while angularly advancing the blades and the web, directing a jet of air at the perforated line in saidweb between the adjacent blades to force said web toward the inner ends of the blades and the fold line in said web supporting sheet, forming an inside fold in the web at the perforated line between adjacent blades by angularly advancing the blades and the web to move the blades into parallel relationship and gripping the web between the folded web supporting sheet and the inner ends of said adjacent blades, linearly advancing said blades and said web downwardly, releasing the web from between the inner ends of said blades by moving the outer ends of the blades angularly apart, and engaging the second surface of the web with a rotating wheel member moving in a direction opposite to that of the blades to remove the folded web from the folder apparatus. 

